Since a die was first invented, no innovative changes have been made in its structure; it has been improved only in the aspect of its material and now came to a state, where coating technique was combined. Structural innovation that enables reduction of production cost and improvement of operational capabilities is highly important in the art. It is to develop a novel die container system with high strength and a safe method of assembling die core to such system by a great force.
The U.S. Pat. No. 4,270,380 provides a die assembly having an interlayer between a die nib and a casing composed of all-crystalline ceramic material having a heating liquidus temperature within the range of 500° C.-570° C. The solidified interlayer maintains uniform shrink-fitted compression on the nib during usage of the assembly, and thus makes it possible to overcome die cracking, its operational capability being improved.
International Patent Application WO 2005058519 describes a diamond die having a die core and at least two pre-stressed rings housing the die core and a method of making the same. The rings may be shrink fit, press-fit, or otherwise formed around each other such that elastic and plastic deformation occurs and the rings are at near yield state, but not yielded state.
A die having an interlayer between the die core and the casing is also explained in Russian Patent No. 1477497, which is characterized in that the yield strength of the interlayer material is 0.5-0.9 times that of the casing material. An interlayer with 0.25 mm thickness is formed by dipping the core in the dissolved interlayer material. The die core coated with interlayer is then shrink-fitted to the pre-heated casing, the inside surface of which is threaded to a meta screw using a chaser prior to fitting. As a result, an easily removable die with longer life time is obtained.
By utilizing the die casings and assembling methods that have been known until now, it is impossible to considerably improve its operational capabilities by fitting the die core with a great force and prevent die cracking when fitting the light weight die core with a great force.
If a die made of wear-resistant materials like hard alloy and extra hard alloy having low tensile strength and high compression strength is assembled by a great force in a safe mode without cracking the die core, its operating capability would be significantly improved.
The aim of the present invention is to attain a long lasting die assembly with an improved operational capability by providing a rigid die container system with great strength and a new method of assembling the die core to it by a great force without die cracking.